Wear and Corrosion Resistance of CrN Films on Oxynitriding-treated Vanadis 8 Tool Steel via the DC Magnetron Sputtering Process

This research coated CrN films on oxynitriding-treated Vanadis 8 tool steel using the DC magnetron sputtering process of the PVD technique. The experimental parameters include different gas flow rates (Ar/N-2 was 20/20, 24/16, 28/12, and 32/8, respectively), with a bias of -50 V, power of 100 W, deposition temperature of 300 degrees C, and deposition time of 180 min, respectively. The experimental results show that Vanadis 8 tool steel can form an effective oxynitriding layer with a depth of about 50 mu m after the oxynitriding treatment, and the surface hardness increased to about 1 400 HV0.05. Furthermore, the duplex coating layers exhibited optimal properties when the CrN films treated at an appropriate gas flow rate of Ar/N-2 was 24/16. Meanwhile, according to XRD analysis, the coating layer has a relatively high content of CrN composition, as well as the best wear resistance (the lowest specific wear rate when the loads of 2 N and 4 N were 2.05 x 10(-5) and 1.56 x 10(-5) mm(3).m(-1).N-1) and good corrosion resistance (in a 3.5 wt% NaCl environment, I-corr = 3.05 x 10(-4) A.cm(-2), R-p = 362.52 Omega.cm(2)). Overall, this study reveals that the CrN/oxynitriding duplex surface treatment could effectively improve the wear and corrosion properties of Vanadis 8 tool steel.